Sustainable metals: science and systems

Decarbonising the global steel industry hinges on three key limited resources: geological carbon storage, zero emission electricity, and end-of-life scrap. Existing systems analysis calls for an accelerated expansion of the supply of these resources to meet the assumed ever-increasing steel demand. In this talk, Dr Watari proposes a different view on how to decarbonise the global steel industry, based on the precautionary principle that resource supply can only expand in line with historical trends and actual construction plans. The analysis shows that global steel production cannot grow any further within a carbon budget and conservative resource supply, resulting in a ~60% shortfall against 2050 demand. The trajectory involves the phasing out of blast furnace production, while recycling-based production will double by 2050, along with modest growth in hydrogen-based production. These findings highlight critical yet often overlooked challenges: (1) reducing demand while providing essential services, (2) producing high-grade steel through upcycling scrap, and (3) ensuring an equitable distribution of recycling-based production across the globe. These perspectives contrast with that of the current agenda, which almost exclusively emphasises the need to invest in new production technologies and resource supplies. Given the slow and staggering progress in decarbonising the steel industry, this talk aims to offer a complementary perspective for a more balanced debate in policymaking and industrial strategy.

Dr Takuma Watari, National Institute for Environmental Studies, Japan

Dr Takuma Watari, National Institute for Environmental Studies, Japan

Takuma is a tenure-track researcher at the National Institute for Environmental Studies, Japan, and a JSPS Research Fellow at Leiden University, the Netherlands. Previously, he worked at the University of Cambridge, UK, and the University of Technology Sydney, Australia. His primary research interests include industrial decarbonisation, responsible supply of critical materials, and international equity in resource use. His work combines traditional engineering principles with systems analysis, and has been published in leading multidisciplinary scientific journals. He currently leads several research projects on sustainable materials use and works closely with government and industry to apply a systems perspective to decision-making.

There is a division in the literature regarding the future availability of low or zero-carbon energy, driven partially by differing estimates of the resource requirements for energy infrastructure. Dr Daehn starts with an investigation into the resource requirements for a net-zero energy system, with a focus on bulk materials and energy inputs. She argues that the infrastructure requirements are largely achievable, and the metals industry can play a key reinforcing role in the transition by adapting to the increasing supply of renewable electricity. Specifically, direct electrolysis can extract metal from ore much closer to the thermodynamic limit, to make efficient use of low-C electricity while decoupling extraction from GHG emissions. The unique features and recent advancements of emerging technologies for iron extraction, molten oxide electrolysis (MOE) and molten sulphide electrolysis (MSE), are described and modelled in this evolving system. Though long time scales are required, electrification enables elegant separations of ore and scrap feedstocks, and provides a pathway to build out abundant renewable energy while continually reducing environmental impacts.

Dr Katrin Daehn, Massachusetts Institute of Technology, USA

Dr Katrin Daehn, Massachusetts Institute of Technology, USA

Katie grew up in Columbus, Ohio and earned her BS in Materials Science and Engineering at the Ohio State University in 2015. She then went onto a PhD in Engineering at the University of Cambridge (completed in 2019) as a Cambridge Trust scholar, working with Professor Julian Allwood on end-of-life steel recycling. She is now a postdoctoral researcher in the MIT Climate and Sustainability Consortium helping to develop cross-sector strategies to decarbonize the global economy. Achievements she is particularly proud of include receiving the Goldwater scholarship, authoring the Top Policy paper in Environmental Science and Technology (2017), and working with a team to extract copper and iron from ore using only electricity in Professor Antoine Allanore’s lab. She is a third-generation metallurgist and wants to spend her career improving the management of Earth’s resources.

The recycling of metals makes a significant contribution to resource and energy efficiency. In this context, however, the entire metal cycle must be considered, including primary metallurgy as well as zero-waste concepts and material design. In addition, today's process technologies are not yet optimized in terms of process engineering and economics with regard to the variety of input materials, scrap and metal-containing residual materials. In particular, the element distributions in the individual phases are not always known. In the case of base metals such as aluminium, magnesium and titanium, the variety of alloys poses a major challenge in the field of recycling technologies, as for the most part no refining options exist. However, the variety of elements, coating and bonding systems in end-of-life products, which are a necessity due to the required functionality, very often means that only a few metals are recovered. Comprehensive multi-metal recycling does not currently exist. This requires research and development in the area of process optimization and the recycling of by-products generated during the processes. Using examples in the field of light and heavy metals, the challenges and possible solutions will be explained and future research priorities discussed. The targeted networking of collection, processing and material recycling as well as the interaction with primary metallurgy are the focus of the considerations.

Dipl-Ing Dr mont Eva Gerold, University of Leoben, Austria

Dipl-Ing Dr mont Eva Gerold, University of Leoben, Austria

Most of the electronic waste, spent batteries and polymer-metal laminated flexible packaging waste are the problematic solid waste streams around the world today which are destined to be stockpiled/landfilled or transported overseas in developing countries. The rapid uptake of technology and energy storage systems with the advent of new designs at regular intervals and intense marketing in the electronics sector and other consumer goods is causing the early obsolescence of many products. However, these waste sources are embedded with valuable metals such as copper, tin, aluminium, cobalt, nickel, lithium, etc. Due to the ongoing demands for valuable metals for different applications, global industrial and manufacturing supply chains must embrace strategies in which conventional resources could be replaced by resources extracted from waste that are currently lost to landfills and other uncertain futures. Selective thermal transformation of waste, in small-scale MICROfactories^TM, can enable decentralised processing of waste resources by businesses large and small, in modular systems, into valuable ‘Green Metals’ for feedstock. This will create stocks of value-added sustainable metal alloys which could become part of supply chains for manufacturing, support the manufacturing and energy industry, and protect the environment. 

Dr Rumana Hossain, Centre for Sustainable Materials Research & Technology, SMaRT@UNSW, University of New South Wales, Australia

Dr Rumana Hossain, Centre for Sustainable Materials Research & Technology, SMaRT@UNSW, University of New South Wales, Australia

Recipient of an Australian Postgraduate award, Dr Rumana Hossain is a material scientist and engineer, an expert on innovative solutions for waste challenges. Her research experience of working with industries and in research commercialisation promotes a culture of innovation to particularly bridge the gap between pure and applied research to transform waste into valuable materials for sustainable manufacturing and environment. Her research activities at SMaRT@UNSW Sydney includes leading industrial projects for waste recycling solutions, publishing in high-impact journals, and building strong networks across diverse industries, communities, national and international research institutions.

An urgent decarbonization of the energy sector is required to combat global warming, as this sector accounts for more than 70% global CO₂ emissions due to the use of fossil fuel. Sustainable energy storage technology is a key to this transition due to the spatiotemporal intermittence of sustainable energy production based on solar, winder, hydropower, and geothermal energies, etc. Recently, metal fuels were proposed as high energy dense and sustainable energy carriers. In particular, iron powder is very promising due to its relatively low-cost, safety, abundance, and facilitated retrofit of the power plants. The stored energy is released during the combustion of the metallic powder. The product of the combustion, iron oxide powder, is then regenerated by hydrogen-based solid-state direct reduction. A net CO₂-free emission closed cycle of energy storage is obtained, when the hydrogen is produced using renewable energy sources. While the first studies on pure iron combustion and regeneration are very promising, the influence of eventual impurities inside the Fe-based powders on the combustion and reduction processes has never been studied. Yet, increasing the tolerated amount of impurities in the iron powder will increase its economic competitiveness, as well as potentially improve the combustion/regeneration processes. During this presentation, Dr Choisez will present an overview of the current understanding of the combustion and hydrogen-based direct reduction of pure iron powders, as well as the expected influence of several impurities on the combustion and regeneration of Fe-based sustainable fuel.

Dr Laurine Choisez, Université Catholique de Louvain, Belgium

Dr Laurine Choisez, Université Catholique de Louvain, Belgium

Dr-Ing Laurine Choisez is currently working at the Université Catholique de Louvain, Belgium, as chargé de recherche FNRS on the topic of sustainable iron powder fuel. She started working on iron fuel during her post-doc at the Max-Planck Institute for Iron Research in 2021. She received her PhD in 2021 at the Université Catholique de Louvain, Belgium, where she also graduated as a materials science engineer in 2016. She also had the opportunity of studying martensitic transformation in ceramic shape memory alloys in 2015 at MIT. Her current research interests lie from metal fuel, iron combustion and hydrogen-based reduction of iron ores to beta-metastable Ti alloys, damage mechanisms and defect tolerant materials for 3D printing. Dr Choisez received the Chair Lhoist Berghmans grant in 2015, the FNRS grant for doctoral researcher in 2016 and the FNRS grant for postdoc research, received in 2022.

At various non-ferrous metal production sites, the production of the main raw metals requires the removal of impurities associated and introduced with the ore concentrates. This extractive metallurgy produces slags, dusts, sludges, or precipitation residues as a byproduct. The current common practice of disposing of these residues not only generates considerable landfill volumes, but also results in the loss of significant quantities of scarce and valuable elements contained in these materials, including nickel, silver, cobalt, indium, and others. The growing awareness of the need for these high-tech metals in the technologies required for the energy transition, climate protection, the electrification of mobility and also for the independence of metal production in Europe, is bringing these materials, which have been ignored for years, back into the focus of science. 

Against this background, the presentation will attempt to discuss the material flows of the base metals industry, such as zinc, lead, copper, or aluminium, the genesis of selected generated residues and their possible contained scarce valuable metals. Using an example from nickel- and zinc-metallurgy, furthermore the challenges and complexity during characterization of these materials and the associated necessary holistic approach during the fundamental research in the area of process development to find scalable solutions will be discussed.

PD Assistant Professor Stefan Steinlechner, Christian Doppler Laboratory, Montanuniversität Leoben, Austria

PD Assistant Professor Stefan Steinlechner, Christian Doppler Laboratory, Montanuniversität Leoben, Austria

Stefan Steinlechner studied metallurgy at the Montanuniversität Leoben in Austria and defended his PhD in the year 2013. Since then, he has been working as a postdoctoral researcher at the Chair of Nonferrous Metallurgy. From 2014 to 2018 Stefan Steinlechner was responsible for a Research-Studio-Austria focusing on energy and resource efficiency in metal recycling from industrial residues. In 2018 he was appointed the venia docendi for the metallurgy of nonferrous metals and since 2020 he has been Head of the "Christian Doppler Laboratory for the selective recovery of minor metals using innovative process concepts". 

As metals are the cornerstone of the sustainable development of our society and have an important contribution to the clean energy transition, a sustainable metals industry is a critical necessity for our future sustainable society. Among the key enablers for sustainable metals systems are stable and sufficient access to resources, climate change neutral or even positive processes, an involved community with engaged professionals and a long-term vision and strategy set by stakeholders, policymakers and public authorities. The establishment of multi-stakeholders partnerships and network collaborations is crucial for this transition to sustainable metals systems. A recent initiative is the launch of Flanders Metals Valley in 2021, a bottom-up initiative in which its members, consisting of companies, universities and knowledge centres, collaborate to create a climate-neutral circular metals industry and to be a stellar example of industrial symbiosis. Within the vision of Flanders Metals Valley, by acting as a network, metals circularity can be improved by jointly developing solutions for particular co-products. The creation of these solutions relies on the close collaboration between industry and knowledge partners to enable ground-breaking innovative research which is supplying answers to the challenges faced by industry today. Dr Malfliet will discuss the role and vision of Flanders Metals Valley in creating a climate-neutral circular metals industry and illustrate the industry-university collaboration for the research in the field of the valorisation of co-products.

Dr Annelies Malfliet, KU Leuven, Belgium

Dr Annelies Malfliet, KU Leuven, Belgium

Dr Ir Annelies Malfliet is a research expert at the Department of Materials Engineering at the KU Leuven, where she is affiliated to the group of High Temperature Processes and Industrial Ecology. Her expertise lies in the field of ferrous and non-ferrous metallurgy, in particular on high temperature metal processing, residue valorisation, metal recovery and vessel integrity. Annelies Malfliet is coordinator of the Centre for High Temperature Processes and Sustainable Materials Management, which is a close collaboration between the research group and leading metallurgical companies in Flanders. She is also member of the steering group of Flanders Metals Valley (FMV), a network of metallurgical companies, research institutes and universities in and around Flanders to stimulate enthusing education and groundbreaking research in the field of climate-neutral and circular metallurgy. She is author of 73 peer-reviewed publications and 7 book chapters.